Differential mechanism



Feb 1942. C. E. FREDERICKSQN 2,272,161

DIFFERENTIAL MECHANISM I Filed April 1, 1940 altar/M41513 29 I i 2 gmwrwj I C lay 0112 fie defz c/fson Patented Feb. '3, 1942 I Clayton ErasmusFrcderlckson, Chicago, Ill. Application April 1, 1940, Serial No.327,309

11 Claims.

My present invention is an improved differential of the type disclosedin my Patent No. 2,203,683, issued June 11, 1950, and the present.pressure angle of the worms H and worm gears I approximately and thehelix cut approxi invention, in its specific aspects, has for an ob.- I

ject to provide improved means for mounting the key-worms in the case.

Another object is to reduce the cost of manufacture and increase thelife of the key-worms and their bearings.

Other objects will in part be obvious and in part be pointed outhereinafter.

To the attainment of the aforesaid objects and ends the invention stillfurther resides in the novel details of construction, combination andarrangement of parts, all of which will be first fully described in thefollowing detailed descrip tion, and then be particularly pointed out inthe appended claims, reference being had to the accompanying drawing, inwhich;

Fig. 1 is a view of one-half the case and its contents, viewed from theplane of separation of the casehalves, the spider and worm pinions beingremoved.

Fig, 2 is a section On the line 2--2 of Fig. 1.

Fig. 3 is a detail viewof one key-worm and its bearings, whichconstitute the specific subject I matter of this application.

In the drawing, the parts which bear the same reference number as likeparts in my aforesaid patent are the same.

.The present construction illustrated differs from that of myapplication above referred to in that three key-worm sets are showninstead of four, and the means to mount the key-worms in the case aredifferent. Any number of keyworm sets, however, may be used as desired,depending upon the resistance required-to operate the vehicle with load.

In the present case each key-worm l l is journaled on a pin or stubshaft 21 which has (preferably) reduced ends 28, 28 tightly pressed orfitted in the holes 33 of the rectangular bearing blocks 29. The blocks29 have flanges 3| to fit grooves 32 in the recesses 39 of the case. Theblocks 29 occupy the full depth of the recesses so that when the casehalves are assembled and secured by the cross bolts 4 the blocks 29 inone side mately 19 35 good results can be obtained in that gear noiseand shock are reduced to a minimum. The above amounts may, however, varyfrom 5 to 10 either way and yet operate successfully,

From the foregoing description, taken in connection with theaccompanying drawing, it is thought that the construction and advantagesof the invention will be clear to those skilled in the art.

What I claim is:

1. In a worm-differential, a case composed of two sections boltedtogether, each section having chambers provided with hearing blockreceiving recesses entering from the plane between the sections,key-worms, shafts on which said keyworms rotate, elongated bearingblocks in which the ends of said shafts are secured and between whichsaid key-worms are positioned, a worm, two bearing blocks and. a shaftconstituting a unit assembly, said case sections recesses being shapedto receive and fit said bearing blocks, and

worm pinions in said chambers to mesh with said key-worms.

2. In a. worm-differential, a case composed of 'two' sections boltedtogether, each section having chambers providedwith bearing blo'ckreceiving recesses entering from the plane between the sections,key-worms, shafts on which said keyworms rotate, elongated bearingblocks in'which the ends of said shafts-are secured and between whichsaid key-worms are positioned, said case sections recesses being shapedto receive and fit said bearing blocks, and worm pinions in saidcharnbersto mesh with said key-worms.

3. In a differential mechanism, a two part case,

each part of which has chambers for receiving driving anddifferentiating worm gears and pinions and connecting key-worms, meansto mount the key worms in the case parts, said means comprising bearingblock receiving recesses entering from the parting plane of the caseparts and extending inwardly therefrom, elongated bearingiblocks in saidrecesses, those of one case part abutting those of the opposite willabut those in the other side and hence the blocks 29 will be tightlysecured in the case and thus maintain the axes of the key-worms alwaysthe same distance from the axes of the worm pinions 20, which aremounted on the stub shafts l8 of the spider.

In the practical construction of my worm differential I have found thatbymaking the normal case part, shafts carried by each pair of blocks,and key-worms rotatable on said shafts between the blocks of a pair.

- 4. In a differential mechanism, a two part case, each part of whichhas chambers for receiving driving and diiferentiating orm gears andpinions and connecting key worms, means to mount the key-worms in thecase parts, said means comprising bearing block receiving recesses en- Itering from the parting plane of the case parts each part of which haschambers for receiving driving and difierentiating worm gears andpinions and connecting key worms, means to mount the key-worms in thecase parts, said means comprising bearing block receiving recessesentering from the parting plane of the case parts and extending inwardlytherefrom, elongated bearing blocks in said recesses, shafts carried byeach pair of blocks, and key-worms rotatable on said shafts between theblocks of a pair, said case having flanges to fit said grooves.

6. In a diiferential mechanism, a two part case, each part of which haschambers for receiving driving and differentiating worm gears andpinions and connecting key worms, and means to mount the key-worms inthe case parts, said keyworms and pinions being constructed so thattheir normal pressure angle is approximately 25 and their helix cut isapproximately 19 35.

7. In a differential mechanism of the character described, a case,key-worms, worm pinions meshing with said key worms, and worm gearsmeshing with said key worms, said key-worms and worm pinions beingconstructed so that their normal pressure angle is approximately 25.

8. In a difierential mechanism of the charac ter described, a casehaving a chamber for receiving driving and difierentiating worm gearsand pinions and connecting key worms, means to mount the key worms forrotation within the case chamber comprising bearing block receivingrecesses communicating with and extending from the case chamber, bearingblocks in said recesses, a shaft carried by each pair of blocks, and akey worm rotatably supported on each shaft between the blocks of a pair.

9. In a worm-differential, a case having a chamber for receivingco-axial worm gears and, meshing therewith, key worm assemblies eachcomprising a pair of bearings, a shaft extended between and connectingthe two bearings, and a key worm rotatably supported on the shaft, andmeans extending away from the chamber in a direction parallel with theaxes of the worm gears afiording a mounting wherein the bearings may beslidably received and immovably retained.

10. In a differential mechanism, a case having chambers for receivingdriving and differentiating worm gears and pinions and connectingkeyworms, means to mount the key-worms in the case parts, said meanscomprising bearing block receiving recesses entering from the partingplane of the case parts and extending inwardly therefrom, elongatedbearing blocks in said recesses, those of one case part abutting thoseof the opposite case part, shafts carried by each pair of blocks, andkey-worms rotatable on said shafts between the blocks of a pair, saidkeyworms and worm pinions being constructed so that their normalpressure angle is approximately 25.

11. In a differential mechanism, a case having chambers for receivingdriving and differentiating worm gears and pinions and connectingkeyworms, means to mount the key-worms in the case parts, said meanscomprising bearing block receiving recesses entering from the partingplane of the case parts and extending inwardly therefrom, elongatedbearing blocks in said recesses, those of one case part abutting thoseof the opposite case part, shafts carried by each pair of blocks, andkey-worms rotatable on said shafts between the blocks of a pair, saidkeyworms and worm pinions being constructed so that their normalpressure angle is approximately 25 and their helix cut is approximately19 35'.

CLAYTON ERASMUS FREDERICKSON.

